Composite parti-resilient body



K.v H. BOWEN coMPsITE 'PARTI-RESINE@ BoDY 1min 194mv Filed July 51.1959

31a/nm I Patented Jan. 9, 1940 UNITED STATES PATENT OFFICE COMPOSITE PARTI-BESILIENT, BODY Y f Kenneth H. Bowen, Auburn, N. Y., assignor to Columbian Rope Company, Auburn, N. Y., a corporation ofNew York Application July si, 1939, serial No. 287,639 15 claim. (o1. 51-195) This invention relates to improvements .in

molded, composite bodies. f

The primary object of the invention is to provide a molded body or member having different characteristics in contiguous portions thereof due to dierences in the bonding materials used in the respective portions.

A further object is to iirmly bond together and unite those portions having diiierent bonding materials notwithstanding the latter possess certain different properties or characteristics. U

Another object is to provide a body having a rigid section and a resilient section, the body in its entirety` being such that it` can be produced ina single molding operation, thus facilitating, and reducing the cost of, production of such bodies.

A further object of the invention is to provide a molded fibre .body or member comprisingr a substantially rigid portion wherein the fibre is impregnated with a thermo-setting binder or, if desired, a thermoplasticy binder, and va flexible portion secured thereto wherein the nbre is impregnated with a resilient binder. These two difsetting of the two binders, although a mechanical interlock may also be used for securing the two portions together.

More specifically, the invention contemplates a composite molded body or member comprising a rigid portion and a iiexible or resilient portion, the rigid portion preferably consistingof a libre ller and a phenol resin binder of the heat-hardening type, and the exible portion consisting of a fibre ller and a exible binder such as latex cement. The two binders should be capable of setting and bonding the two differentportions of the member or body securely together but, if desired, the two portions can be mechanically interlocked into one another to secure them together.

Another object of the invention is to provide an abrading pad, one portion of. which is substantially rigid and another portion of which possesses exibility or resiliency. Where the pad is to be usedfor polishing, it is preferred that the flexible portion take the form of an annular member surrounding a hub portion which is substantially rigid and capable oi.' being formed ,withY athreaded aperture for mounting on an actuating shaft. Where the vpad is to be used as a floor sander, the flexible portion and the rigid portion are of disc-like formation, laidI one upon 55 the other, the rigid portion forming a for ferent portions may be secured together by the 1 the exlble portion and being capable of being apertured and threaded for mounting on a shaft. A still further object is to provide a composite molded body capable of absorbing or dampening vibrations or shocks, said member consisting of substantially rigid portions' of the nature described, with `an interposed flexible portionof the character above set forth, whereby the tendency of the rigid portions to move toward one another will flex the ilexible portion and thus absorb or dampen impacts which tend to move the separated rigid portions toward one another. With these and otherobiects in view, the invention'consists in certain details of construction and combinations and arrangements of parts, all

Y as will hereinafter be morefully described, and

the novel featuresGthereof particularly pointed out in the appended claims.

In the accompanying drawing- Figure 1 is a plan view of a polishing pad made in accordance with the present invention;

Fig. 2 is a transverse sectional view on the'line 2-.2 of Fig. l;

Fig. 3 is a view similar to Fig. 2, illustrating 25 a floor sanding pad;

Fig. 4 isa perspective view oi a shock or vibration dampening member made in accordance with the present invention; and

Fig. 5 is'a ltransverse sectional view of the vibration dampener.

In view of vdilculties heretofore encountered in securing cohesion between metal and rubber by bon'ding the rubber to the metal, it has generally been the practice .to plate the metal with copper or brass. In fact, in the absence loi? the plating step, it hasbeen deemed practically impossible tobond rubber to metal so that the two will prop-l erly adhere to one another. I have discovered,

however, that certain bonding materials, al-

though possessigng certain different characteristics, can be bonded together to flrmly'unite portions of a bodyor member possessing character,

istics, depending upon the varying properties of the bonding materials used. In view of this, I

vhave produced various molded bodies comprising substantially rigid portions and other iiexible portions, the rigid portions being composed of a fibre ller and a. thermo-setting binder,. or a; thermo-plastic binder, and the exible portion. being composed of 1a bre ller and a exible thermo-plastic binders, such as cellulose acetate.

binder such as latexoement. Preferably, a pheethyl cellulose and similar plastic materials. In molding a body under pressure and heat, the libre impregnated with the phenol resin binder becomes very rigid and is well capable of being machined. On the lother hand, the latex cement retains its property of resiliency upon the application of such heat and pressure as is used in setting the phenol resin binder. Thus, that portion of the body composed of the fibre ller and latex cement binder possesses a high degree of ilexibility or resiliency. At the same time, it will be found that the two binders have so fusedtogether that when set under heat and pressure the two portions of the body are rather firmly secured together by the bonding action of those bonding materials.

For instance, as illustrated in Figs.,1 and 2, a polishing pad can be produced from two such bodies of fibres impregnated with bonding materials of different natures. In the case of the polishing pad, there is a hub portion III formed of a bre ller, preferably vegetable bres, and a phenol resin or thermo-setting binder, and surrounding said hub portion there is an annular peripheral portion II formed of iibre, also preferably vegetable bre, and a latex cement binder. Preferably, in molding this pad, a number of plies or thicknesses of the material, which are to constitute the hub, and which are in the form of discs, are placed in the mold and then the required number of thicknesses of the material, which are to constitute the annular portion II, are placed in the mold. Each of these thicknesses forming the annular portion Il is in the form of an annulus having a bore less than the diameter of the discs constituting the hub. Thus, the'` inner edges of the plies of material constituting the peripheral portion I I overlap the edges of the discs which are to form the hub. After this, additional thicknesses of material constituting the hub are placed in the mold with the edges of the upper thicknesses overlapping the exposed surface of the inner edge of the material which is to constitute the peripheral portion II. In other words, the plies of material constituting the peripheral portion II are interiitted between upper and lower plies which are to constitute the hub portion I 0, The loadedmold is then subjected to pressure and heat, in accordance with usual molding practices, to form the pad illustrated, in section, in Fig. 2. As will be seen, the inner edge of the annular peripheral portion I I is interfittedor interlocked, so to speak, with the top and lower portions of the hub I0, due to the mannerV in which the mold was loaded with the several thicknesses of the two materials.l This mechanical interlock might well be relied upon for securing the two sections together because the pressure used in the molding flrmlysecures the interfittingportions together.

1 As previously7 stated, the setting of the phenolic resin binder by the application of pressure and heat produces a very strong rigid and hard hub. As illustrated, this hub is formed with a.

threaded aperture to receive the threaded end of a shaft I2 for rotating the pad. The aperture may be formed in the hub during the molding operation or later, preliminarily to the threading operation. The operative face of the pad is.

adapted to be provided with an abrading surface. For instance, it may be provided with a sheet of emery paper or sand paper I3. When mounted on the hub, this sheet of abrading materialis held in place by the nut I4 which also secures the pad on the threaded end oi Schaft I2.`

While the hub portion I is very-strong and hard, the peripheral annular portion II possesses the desired resiliency in that, when placed in operation with the hub disposed at an angle to the surface being polished, the peripheral portion can bend or flex backwardly. At the same time,

' it will be found that the hub portion and peripheral portion are rmly secured together mechanically as well as by the bonding action of both the latex cement in the peripheral portion II and the phenolic resin binder in the hub portion I0. As "previously stated, the interiitting relationship of the hub portion and peripheral portion may, alone, be relied upon for maintaining the unitary arrangement of the two sections. It will be obvious that this interfitting relationship is not necessarily limited to the inner edgev of the peripheral portion extending into the recess formed in the perimeter of the hub portion as the several laminations might well be placed in the mold in such fashion as to have the material constituting the hub project in between plies of material constituting the annular portion I I.

In the case of the oor sanding pad, the operative face of the pad should be backed or reinforced throughout substantially its entire area as it is applied more or less flat against the surface of Athe oor. Consequently, in molding these pads, a number of discs of iibre impregnated with latex cement are rst placed in the mold and then the desired number of thicknesses of fibre impregnated with the phenolic resin binder are superimposed thereon in the mold, after which heat and pressureare applied to the mold, as above outlined in connection with the molding of the polishing pad. The operative face of the oor sanding pad, formed of iibre and latex cement binder, constitutes the resilient or iiexible portion I5 of the body, and this flexible portion is backed, so to speak, by the rigid portion I6,

which i's formed of fibre and the phenolic resin binder, the operative portion and the back-ing portion being usually of the same circular dimension. In this instance, it will also be noted that the backing portion I6 is provided with an aperture I1 therein and the wall of said aperture threaded for mounting the pad on its actuating shaft. Here, again, the two portions-the resilent portion I5 and the substantially rigid backing portion I6-are securely united over their entire contacting surfaces by the bonding properties of both the latex cement binder and the phenolic resin binder.

In the Vibration dampener illustrated in Figs. 4 and 5, the composite member is formed ofa substantially rigid baseportion I8 and a substantially rigid top portion I9 held in spaced relationship with respect to the base I8 by an intermediate resilient, flexible portion 20. Both the base I8 and the top I9 are formed of libre impregnated with phenolic resin binder. In the structure actually shown in Figs; 4 and 5, the base I8 and top I9 are preferably in the form of an annulus an-d a disc, respectively. On the other hand, the intermediate flexible portion is formed of the fibre impregnated with the exible binder such as latex cement and when the entire composite body is molded under pressure and heat, these several portions are securely bonded together by the action of these bonding materials. In use, one of the portions I8 or I9, but usually the base I8, will be mounted upon a rm support and'l the other portion, in this instance the top I9, is adapted to receive -the impacts or shocks that are to be absorbed or dampby the intermediate flexible portion 20 by reason of the exing of this portion veach time lthere is al tendency of the top I9 to move toward the base I8.

While the latex cementbinder is preferred for' impregnating the resilient portions of composite bodies made in accordance with the present in- "vention, it is also possible to use certain types of resin binders. There are, at present, on the market, flexible or. plasticized resin binders, which can be utilized in the vflexible portions of the composite member. Thus, the resin binders of this last-mentioned type do not impart rigidity to the impregnated bres that are to constitute .the exible portions ofv the composite moldedA body.

What I claim is: l

1. A composite body having a rigid portion consisting of a bre ller impregnatedv with a thermo-settingtbinder and a exible portion con-` sisting of a fibre iillerand a flexible binder, said two portions being securely bonded together by said binders.

2. A composite body having a rigid portion,

composed essentially of a fibre filler anda phenol resin binder of the heat-hardening type and a vresilient portion consisting essentially of a libre ller impregnated with a latex cement binder, said two portions being securely bonded together Vby said binders. 4

v3. A composite body composed essentially of a l:libre illler and binder material, onel portion of saidvbody being impregnated with a phenolic resin binder of Athe heat-hardening type and a second portion impregnated with a flexible resin binder set by baking,. said two' portions being' by thebonding acwhen set and a iiexible section consisting of a.y

vegetable ibre filler and a resilient binder, portions of said two sections being mechanically inl terlccked with one another.

6. An abrading pad composed of bre ller and binder material, and having a hard, rigid h ub section encircled by a flexible annular peripheral section, portions of said two sections being mechanicallyinterlocked with one another.

7.An abrading 'pad composed of a rigid hub section formed of a fibre illler and phenolic resin binder and a exible peripheral portion encircling said hub section, said peripheral portion being formed of a iibre iiller and a'resilient binder, and a mechanical interlock iirmly uniting said hub section and peripheral portion.

8. An abrading pad'having arigid hub section formed o f fibres and a thermo-setting bindv er and a hub-encircling, exible peripheral section formed of libres and a resilient binder, the

bres o1' one section being arranged in plies 1' with the-edges of plies of said section overlapping the other section to secure the two sections toj gether.

9. An abrading pad having a rigid hub section formed of libres and a thermo-setting binder and -a hub-encircling,exible peripheral section formed of bres and a resilient binder, the :fibres of each section being arranged in plies with plies of one section projecting between plies of the other section to form a mechanical interlock between the two sections.

10. An abrading pad formed ci a substantially rigid portion and a exible, resilient portion, said rigid portion being composed of a nbre filler impregnated with a phenol resin binder of the heathardening type Aand said flexible portion being formed of a libre ller and a iiexible binder, the two portions being securely attached .by the bondingcuon o f their binders. g

11. An abrading pad having a substantially rigid central hub portion with an aperture formed axially thereof, the wall ofl said aperture being threaded for attachment to an actuating shaft, and aA flexible peripheral portion surrounding said hub portion, the perimeter'l of said hub portion-and the inner edge of said peripheral portion being arranged in overlapping relationship, veach oi said portions being formed of a libre ller and a binder, the overlapping areas of the two sections being securely attached together by the bonding action of the binder material' therein,

-12. vA iloor'sandingpad comprising a resilient working face portion formed of a bre filler and ya resilient binder and a backing for said working portion formed .pf a fibre iiller and a phenol resin binder of the heat-hardening type, said working portion and backing being iirmly secured together `by the binder materials carried thereby. 13. A iioor sanding'pad comprising a resilientl working face portion formed of a iibre ller anda resilient binder and a backing for s'aid working'- portion formed of a bre filler and a phenol resin' binder of the heat-hardeningv type, said working portion and backing' being rmly secured to- I gether by the binder materials carried thereby,

and 'said backing having a threaded aperture therein for`mounting on a shaft.

14. A composite shock absorbing memberl composed of-.aresilientbody of fibre ller and resilient binder interposed between substantially rigid bodies of iibre impregnated with a phenol resin binder of the heat-hardeningtype.. all of said bodies being rmly united in saidmember by ,said binder materials.

15. A composite shock absorbing membercomposed of a substantially rigid annulus formed KENNETH H. 

